Adjustable chair, in particular to prevent users from deep vein thrombosis (DVT)

ABSTRACT

An adjustable chair for supporting a user in either a traditional seated position in which a pair of legs of the user rest upon a floor, or in a relaxed seated position in which at least one of the legs of the user are supported above the floor, provides a base supporting an aft cushion assembly, a forward cushion assembly, and an upwardly extending seat back which cooperate to support the user in a seated position. The forward cushion assembly being movably attached to the aft cushion assembly with a movement assembly which allows both horizontal and vertical movement of the forward cushion assembly. The aft cushion assembly being adjustable attached to the base with an adjustment assembly which allows adjustment of the angle of the aft cushion assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to adjustable chairs, and more particularly to an adjustable chair for application in all places where people are sitting for a long period of time, like for example in computer work places as an office seat, in airplanes or busses as a passenger seat, or for disabled people to offer more comfort and to prevent users from Deep Vein Thrombosis (DVT).

2. Description of Related Art

An adjustable chair has been developed to support the human body in a restful and comfortable position and in a relaxed seated position in which both legs of the user are lifted off the floor. Jonas, U.S. Pat. No. 6,578,915, teaches such an adjustable chair, which is especially meant for use in airplanes or busses where the lack of movement resulting from being confined to one's seat might contribute to medical conditions such as DVT, a condition which can be fatal. The known adjustable chair prevents users from DVT by moving their legs up. The mere lifting of the legs off the floor reduces muscle pressure and tension, significantly improving the passenger's feeling of well-being. By moving the legs of the users even off of the floor, they can swing their legs which further reduces the risk of DVT.

Below are some of the factors that may put a person at risk for developing DVT according to doctors. The more factors a person has, the greater the risk: over 40 years of age, who have had blood clots already, with a family history of blood clots, suffering from or who have had treatment for cancer, with certain blood diseases, being treated for heart failure and circulation problems, who have had recent surgery especially on the hips or knees, who have an inherited clotting tendency. DVT is also more common in women who are pregnant, have recently had a baby, are taking the contraceptive pill, are on hormone replacement therapy. Cancer (although having a clot does not necessarily mean that you have cancer) and chemotherapy. Certain congenital heart defects. Congestive heart failure. Chronic respiratory failure. Hormone replacement therapy (often administered to postmenopausal women). Obesity. Prior DVT. Prolonged immobility or paralysis. Stroke. Surgery, including orthopaedic, pelvic, and abdominal surgeries (which can trigger the formation of blood clots). Trauma. Varicose veins (varicosities).

In said known adjustable chair in the lifted position of the legs only the part of the thighs near the knees are supported by a forward cushion assembly. The part of the thigh at distance from the knees is more or less lifted from the aft upwardly facing surface. The muscle pressure and tension of the thighs near the knees is still quite high.

Further for some users the simultaneous lifting of both legs is disadvantageous. For example for pregnant women or overweight people, when lifting both legs undesired forces can be acted on their body. Further some kind of disabled people can not swing or lift their legs, like paralyzed people. So the known chair device doesn't offer an optimal solution for these kinds of persons. Also for other kinds of users the simultaneous lifting of both legs can cause some problems and discomfort.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to improve the known adjustable chair. To this end the present invention provides an adjustable chair for supporting a user in either a traditional seated position in which a pair of legs of the user rest upon a floor, or in a relaxed seated position in which at least one of the legs of the user is lifted with respect to the traditional position. The adjustable chair includes a base supporting an aft cushion assembly, a forward cushion assembly, and an upwardly extending seat back. The aft cushion assembly providing an aft upwardly facing surface, the forward cushion assembly providing a forward upwardly facing surface, and the upwardly extending seat back providing a front facing surface. The aft upwardly facing surface, the forward upwardly facing surface, and the front facing surface cooperate to support the user in a seated position. Said chair further comprises moving means for moving the forward cushion assembly while a user is sitting on the chair. Said moving means being able to move the vertical position of the forward upwardly facing surface with respect to the aft upwardly facing surface to an extent at which the forward upwardly facing surface is at a vertical distance from the aft upwardly facing surface. And said chair further comprises adjusting means for adjusting the angle of at least a part of the aft upwardly facing surface with respect to the base, to support the aft of the user when the forward upwardly facing surface is moved to a position at a vertical distance from the aft upwardly facing surface. The adjusting means can be operated mechanically or manually.

Preferably, said adjusting means further being able to adjust at least a part of the angle of the aft cushion assembly with respect to the base.

Further, said moving means preferably being able to move the forward cushion assembly to an extent at which the forward cushion is at a vertical distance from the aft cushion assembly.

Preferably in each vertical position of the forward cushion assembly the forward cushion assembly being able to move freely in a horizontal direction. The advantage of this is that the user more easily can swing his legs because of the free horizontal movement of the forward cushion assembly. The blood circulation will be improved during swinging which further reduces the risk of DVT.

The moving means further being able to move the forward cushion assembly in a horizontal direction to an extend at which said forward cushion assembly is at a horizontal distance from the aft cushion assembly and contacts a lower thigh portion of the legs of the user. This is advantageous especially for long people to offer a better support for their legs.

On the other hand, in an embodiment which is advantageous for short people and children, the forward cushion assembly being removable from the chair or the forward cushion assembly being movable (mechanically or manually) to a position underneath the aft cushion assembly, so that short people can sit in a normal way, which means that they can bend their knees while sitting with their back against the seat back.

In a further embodiment of the adjustable chair of the present invention the forward cushion assembly comprises two forward cushions adjacent to each other, one for supporting each leg of the user, said two forward cushions are independently movably attached to the aft cushion assembly or to the base. The adjustable chair further includes means for moving the forward cushions, with respect to the aft cushion assembly, such that each leg of the user can be moved independently.

In yet a further embodiment the chair further comprises means for controlling the moving means at least such that the moving means can move the forward cushions continuously or intermittently up and down and/or forwards and backwards. This feature is especially advantageous for disabled people, like paralyzed people, who can not swing or lift their legs. By moving the legs a better blood circulation will be achieved which significantly reduces the risk of DVT.

The adjustable seat according to the invention also offers more comfort to people, especially tall people, as they actually have more leg room and can feel more at ease.

Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the present invention. In such drawings:

FIG. 1 is a perspective view of a first embodiment of the adjustable chair of the present invention designed as an airplane chair with the forward cushions in a traditional seated position;

FIG. 2 is a perspective view similar to that of FIG. 1 of the adjustable chair with one of the forward cushions in a relaxed seated position;

FIG. 3 is a side elevational view of the embodiment shown in FIG. 1 with a person sitting on the chair in a traditional seated position;

FIG. 4 is a side elevational view similar to that of FIG. 3 with one of the legs of the person in a relaxed position;

FIG. 5 is a perspective view of a movement assembly that movably connects the forward cushion assembly to the aft cushion assembly; and

FIG. 6 is a second perspective view of the movement assembly;

FIG. 7 is a perspective view of a second embodiment of the adjustable chair of the present invention designed as a wheelchair with the forward cushions in a traditional seated position;

FIG. 8 is a perspective view similar to that of FIG. 7 of the adjustable chair with one of the forward cushions in a relaxed seated position.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1 and 2 a first embodiment of the adjustable chair 1 according to the invention is shown with the forward cushion assembly 19 in a traditional seated position (FIG. 1) and with the forward cushion assembly in a lifted, relaxed seated position (FIG. 2). In FIGS. 3 and 4 the chair 1 is shown with a person 7 sitting on it, in a position in which the legs 9, 11 of the user resting upon a floor 13 (FIG. 3) and in a position in which the legs 9, 11 are lifted off the floor 13 (FIG. 4).

As shown in FIGS. 1 and 2, the adjustable chair 1 includes a base 15 supporting an aft cushion assembly 17, a forward cushion assembly 19, and an upwardly extending seat back 21. In this embodiment the forward cushion assembly 19 comprises only one forward cushion 3. The aft cushion assembly 19 provides an aft upwardly facing surface 23. The forward cushion 3 provides a forward upwardly facing surface 25. The upwardly extending seat back 21 provides a front facing surface 29. The aft upwardly facing surface 23, the forward upwardly facing surface 25, and the front facing surface 29 cooperate to support the user in a seated position. The upwardly extending seat back 21 is preferably attached to the aft cushion assembly 17 with a seat back hinge 26, although in an alternative embodiment (not shown) the seat back hinge is attached directly to the base 15. The forward cushion assembly 19 is adjustably attached to the aft cushion assembly 17 as described in more detail below. A typical seat having generally similar construction is disclosed in Jonas, U.S. Pat. No. 6,578,915, which is hereby incorporated by reference.

The aft cushion assembly 17 is adjustably connected to the base 15 with a hinge 27 near the middle of the aft cushion assembly, see FIGS. 3 and 4. The chair 1 comprises an adjusting means, schematically shown by an adjustment assembly 30, which can adjust the angle of the front part 17 a of the aft cushion assembly 17 with respect to the base 15.

The forward cushion assembly 19 and the aft cushion assembly 17 are connected with a means for moving the forward cushion 3, thereby moving the legs of the user. The moving means comprises a movement assembly 31 which is shown in detail in FIGS. 5 and 6.

The movement assembly 31 allows both horizontal and vertical adjustment of the forward cushion 3. The movement assembly 31 includes a horizontal slide bar guide 33 mounted on the aft cushion assembly 17, and a slide frame 35 that has a horizontally extending horizontal slide bar 37 and a vertically extending vertical slide bar guide 39. The horizontal slide bar 37 slidably engages the horizontal slide bar guide 33 for horizontal movement of the slide frame 35. The movement assembly 31 further includes a vertical slide bar 41 mounted on the forward cushion 5. The vertical slide bar 41 slidably engaging the vertical slide bar guide 39 for vertical movement of the forward cushion 3. The movement assembly 31 is preferably constructed of a strong, rugged, rigid material such as steel or aluminium.

The movement assembly 31 further includes a locking mechanism 43 that locks the forward cushion 3 into a selected position. The locking mechanism 43 is capable of being moved from a locked position to an unlocked position for adjustment of the forward cushion 3; but a biasing means for biasing the locking mechanism 43 from the unlocked position to the locked position, thereby preventing further movement of the forward cushion 3. The locking mechanism 43 further includes a horizontal pin 45 and a vertical pin 47. In the locked position, the horizontal pin 45 removably engages one of a plurality of horizontal locking holes 49 in the horizontal slide bar guide 33; and the vertical pin 47 removably engages one of a plurality of vertical locking holes 51 in a forward slide plate 53 attached to the forward cushion 3.

The biasing means is preferably a spring 55 operably attached to both a bell crank 57 and a bell crank mounting plate 59. The bell crank mounting plate 59 is preferably fixedly mounted on the forward cushion 3. The bell crank mounting plate 59 preferably includes a bell crank pivot point 61 upon which the bell crank 57 is pivotally mounted. The bell crank 57 has a bell crank pin 63 that engages a locking slot 65 of the locking mechanism 43. In use, the spring 55 biasing the bell crank 57 such that the bell crank pin 63 biases the locking mechanism 43 towards the locked position.

The locking mechanism 43 further includes an unlocking means 67 for overcoming the bias of the spring 55 to move the locking mechanism 43 from the locked position to the unlocked position, wherein the horizontal and vertical pins 45 and 47 are pulled from the horizontal and vertical locking holes 49 and 51, respectively, thereby allowing the forward cushion 3 to be moved. Release of the unlocking means 67 allows the spring 55 to return the locking mechanism 43 to the locked position. The unlocking means 67 preferably includes a handle 69 slidably mounted on a handle guide 71 of the forward cushion 3. The handle 69 is pivotally attached to a lever arm 73 of the bell crank 57 with a handle link 75 such that pulling the handle 69 causes the handle link 75 to pull the lever arm 73. The lever arm 73 causes the bell crank 57 to rotate about the bell crank pivot point 61 against the bias of the spring 55, thereby causing the bell crank pin 63 to move the locking mechanism 43 towards the unlocked position. The unlocking means 67 can also be blocked in a position in which the locking mechanism 43 is in a unlocked position so that the forward cushion 3 can be moved up and down and/or forwards and backwards continuously by the movement assembly 31.

For continuous moving the forward cushion the movement assembly comprises two gas cylinders 77, 79. The slide frame 35 is connected to a piston 81 of the gas cylinder 77 for horizontal movement of the forward cushion 3. The gas cylinder 77 is connected to a control means 83 for controlling the operation of the gas cylinder 77 and thus the horizontal movement of the forward cushion 3, by controlling the valves (not shown) for the gas flow from and to the gas cylinder 77. The forward cushion 3 is connected to a piston 85 of the gas cylinder 79 for vertical movement of the forward cushion 3. Also this cylinder 79 is connected to the control means 83 for controlling the operation of the gas cylinder 79 and thus the vertical movement of the forward cushion 3. The control means 83 comprises a housing with electronic means inside, said housing is connected to the gas cylinder 77. The gas cylinder 77 is connected to the aft cushion assembly 17 or to the horizontal slide bar guide 33. The gas cylinder 79 is connected to the slide frame 35.

The control means can be operated by a control panel (not shown) on an armrest of the adjustable chair 1. The gas cylinders 77 and 79 are similar to other gas cylinders well known in the art, such as Bauer, U.S. Pat. No. 3,711,054, and Claus et al., U.S. Pat. No. 6,116,555, hereby incorporated by reference. Of course, those skilled in the art will recognize that the pistons 81 and 85 and the gas cylinders 77 and 79 can be reversed, or replaced with an equivalent mechanism such as an electrical solenoid, and such modifications should be considered within the scope of the invention.

While the embodiment of the means for horizontal and vertical movement of the adjustable chair 1 have been described in detail, it is recognized that those skilled in the art can devise countless equivalent mechanisms to accomplish the goal of suitably adjusting the forward cushion assembly 19 and the forward upwardly facing surface 25. Structures that are considered equivalent include, but are not limited to pneumatic adjustment devices, motor driven and power assisted devices, and various mechanical adjustment mechanisms such as can be readily devised by those skilled in the art. These equivalent structures should be construed as within the scope of this invention and accordingly within the scope of the claims, below.

Although the preferred embodiment has been described above, those skilled in the art will recognize that modifications to the preferred embodiment can be made without altering the basic structure of the invention. For example, in the normal seated position, the forward upwardly facing surface 25 could not be in contact with the user; in this situation the thigh supporting surface could be another surface of the forward cushion assembly 19. In the relaxed seated position the forward cushion assembly 19 could be rotated and lifted, so that the thigh supporting surface would become the forward upward facing surface 25 of the forward cushion assembly 19 that supports the thighs of the user. Other similar modifications should be considered equivalent to the invention as described in the claims.

In FIGS. 7 and 8 a perspective view of a second embodiment of the adjustable chair of the present invention is shown designed as a wheel chair 91. Those parts of the wheel chair 91 which are similar to that of the chair 1 of the first embodiment are referred to with the same reference numbers. In this embodiment the forward cushion assembly 19 comprises two forward cushions 3, 5.

The moving means can move the forward cushions independently of each other at any speed and over any horizontal and/or vertical distance. On the other hand the moving means can also move the two forward cushions simultaneously up and down and/or forwards and backwards. In this case the two forward cushions could also be connected to each other by a connecting mechanism (not shown). In this embodiment of the adjustable chair 91 according to the invention, the moving means comprises two identical movement assemblies 31.

In FIG. 7 the forward cushions 3, 5 of the wheel chair 91 are in a traditional seated position, whereas in FIG. 8 one of the forward cushions (cushion 5) is in a lifted, relaxed seated position. The footrests 93 and 95 could be connected to the forward cushions 3 and 5 by a mechanism (not shown), for example like a pedal mechanism, so that for example by pushing the right feet the right footrest 93 will go down and lifts the left forward cushion 5. Instead of this mechanism operated by feet also other mechanisms are possible which can be operated by the thighs or hands of the user.

In this embodiment of the chair the aft cushion assembly 17 comprises two aft cushion halves 17′ and 17″, each being adjustably connected to the base 15 with a hinge (not shown) near the seat back 21. The chair 91 further comprises two adjusting means (not shown), each for adjusting the angle of one of the halves 17′, 17″ of the aft cushion assembly 17 with respect to the base 15.

While the invention has been described with reference to two preferred embodiments, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims. 

1. An adjustable chair for supporting a pair of legs of the user, the chair comprising: a base supporting an aft cushion assembly, a forward cushion assembly, and an upwardly extending seat back; the aft cushion assembly providing an aft upwardly facing surface, the forward cushion assembly providing a forward upwardly facing surface, and the upwardly extending seat back providing a front facing surface, the aft upwardly facing surface, the forward upwardly facing surface, and the front facing surface cooperating to support the user in a seated position; and moving means for moving the forward cushion assembly while a user is sitting on the chair, said moving means being able to move the vertical position of the forward upwardly facing surface with respect to the aft upwardly facing surface to an extent at which the forward upwardly facing surface is at a vertical distance from the aft upwardly facing surface, wherein said chair further comprising: adjusting means for adjusting the angle of at least a part of the aft upwardly facing surface with respect to the base, to support the aft of the user when the forward upwardly facing surface is moved to a position at a vertical distance from the aft upwardly facing surface.
 2. The adjustable chair of claim 1 wherein said adjusting means further being able to adjust the angle of at least a part of the aft cushion assembly with respect to the base.
 3. The adjustable chair of claim 1 wherein said moving means further being able to move the forward cushion assembly to an extent at which the forward cushion is at a vertical distance from the aft cushion assembly.
 4. The adjustable chair of claim 1 wherein the forward cushion assembly being removable from the chair.
 5. The adjustable chair of claim 1 wherein the forward cushion assembly being movable to a position underneath the aft cushion assembly.
 6. The adjustable chair of claim 1 wherein in each vertical position of the forward cushion assembly the forward cushion assembly being able to move freely in a horizontal direction.
 7. The adjustable chair of claim 1 wherein said moving means further being able to move the forward cushion assembly in a horizontal direction to an extend at which said forward cushion assembly is at a horizontal distance from the aft cushion assembly and contacts a lower thigh portion of the legs of the user.
 8. The adjustable chair of claim 1 wherein: said forward cushion assembly comprises at least two forward cushions adjacent to each other, one for supporting each leg of the user, and said moving means comprises at least two movement assemblies one for each forward cushion, said movement assemblies being able to move the forward cushions independently of each other in a vertical and/or horizontal direction.
 9. The adjustable chair of claim 8 wherein the moving means are automatically operated means and wherein the adjustable chair further comprises means for controlling the moving means at least such that the moving means can move the forward cushions continuously or intermittently up and down and/or forwards and backwards.
 10. The adjustable chair of claim 8 wherein the moving means are manually operated means, preferably operated by the feet or thighs or hands of the user of the chair at least such that the moving means can move the forward cushions continuously or intermittently up and down and/or forwards and backwards. 